perf: index `running` and `is_bridge` in `server_status`

We should add indexes to server_status for columns running and is_bridge as these are heavily used for filtering rows by Network Status APIs. Currently those are not indexed so queries take a lot of time

i.e

SELECT
count(CASE WHEN is_bridge THEN 1 END) AS total_bridges,
count(CASE WHEN NOT is_bridge THEN 1 END) AS total_relays
FROM server_status;

○ Total Cost: 398,897.1
○ Planning Time: 1.12 ms
○ Execution Time: 947.77 ms
┬
│
└─⌠ Aggregate [Plain]
  │ Groups records together based on a GROUP BY or
  │ aggregate function (e.g. sum()).
  │ ○ Duration: <1 ms (0%)
  │ ○ Cost: 0.01999999996041879 (0%)
  │ ○ Rows: 1
  ├►  count(CASE WHEN is_bridge THEN 1 ELSE NULL::integer
  │  END) + count(CASE WHEN (NOT is_bridge) THEN 1 ELSE
  │  NULL::integer END)
  │
  └─⌠ Gather
    │
    │ ○ Duration: 54.07 ms (6%)
    │ ○ Cost: 1,000.2000000000116 (0%)
    │ ○ Rows: 3
    │   rows Underestimated by 1.50x
    ├►  (PARTIAL count(CASE WHEN is_bridge THEN 1 ELSE
    │  NULL::integer END)) + (PARTIAL count(CASE WHEN (NOT
    │  is_bridge) THEN 1 ELSE NULL::integer END))
    │
    └─⌠ Aggregate [Plain]
      │ Groups records together based on a GROUP BY or
      │ aggregate function (e.g. sum()).
      │ ○ Duration: 583.38 ms (62%)
      │ ○ Cost: 9,793.299999999988 (2%)
      │ ○ Rows: 1
      ├►  PARTIAL count(CASE WHEN is_bridge THEN 1 ELSE
      │  NULL::integer END) + PARTIAL count(CASE WHEN (NOT
      │  is_bridge) THEN 1 ELSE NULL::integer END)
      │
      └─⌠ Seq Scan  slowest   costliest   largest
        │ Finds relevant records by sequentially scanning
        │ the input record set. When reading from a table,
        │ Seq Scans (unlike Index Scans) perform a single
        │ read operation (only the table is read).
        │ ○ Duration: 1.01 s (212%)
        │ ○ Cost: 388,103.58 (97%)
        │ ○ Rows: 1,564,935
        │   on public.server_status
        │   rows Overestimated by 1.25x
        ⌡► is_bridge + published + nickname + fingerprint +
           or_addresses + last_seen + first_seen + running
           + flags + country + country_name +
           autonomous_system + as_name +
           verified_host_names + last_restarted +
           exit_policy + contacts + platform + version +
           version_status + effective_family +
           declared_family + transport +
           bridgedb_distributor + blocklist +
           last_changed_address_or_port + diff_or_addresses
           + unverified_host_names +
           unreachable_or_addresses +
           overload_ratelimits_version +
           overload_ratelimits_timestamp +
           overload_ratelimits_ratelimit +
           overload_ratelimits_burstlimit +
           overload_ratelimits_read_count +
           overload_ratelimits_write_count +
           overload_fd_exhausted_version +
           overload_fd_exhausted_timestamp +
           overload_general_timestamp +
           overload_general_version